The application area of the present invention has been developed in connection with low tariff international telephone-to-telephone calls using the Internet as the main carrier network, but the general aspect of the invention may also be related to any quality of service required.
Furthermore, the present invention is applicable not oly to international and long distance services but also to any other geographically segmented services (e.g. local, regional, national).
Users have telephones connected to the PSTN/ISDN network. The Internet can be used to carry portions of the traditional PSTN/ISDN telephone-to-telephone calls. Special Internet telephony gateways GW form bridges between the PSTN/ISDN access network and the Internet (which acts as the carrier network).
In a traditional telephone-to-telephone call, a connection between two parties is established at the call set-up phase. The originating party and the terminating party are identified by their respective telephone numbers (caller A-num and callee B-num) during the set-up phase. Call logic is handled by the PSTN/ISDN network. In a telephone-to-telephone call using the PSTN/ISDN network as the access network and the Internet as the main carrier network, connections must be established between the user telephones and the gateways that bridge the call. The present invention presents a solution to the handling of call-establishment to the originating gateway. Extensions and enhancements to the basic invention are described later.